The accurate identification of delay time in millisecond blasting plays an important role in the optimization of blasting design and reduction of vibration effect. Through a case study of a surge shaft blasting projec...The accurate identification of delay time in millisecond blasting plays an important role in the optimization of blasting design and reduction of vibration effect. Through a case study of a surge shaft blasting project, the capability of the EMD （empirical mode decomposition） method in identifying the delay time of short millisecond blasting with precise initiation was compared with the instantaneous energy method based on Hilbert-Huang transform （HHT）. The recognition rate of the EMD method was more than 80%, while the instantaneous energy method was less than 25%. By analyzing the instantaneous energy of single-hole blasting signal, it was found that the instantaneous energy method was adaptable to millisecond blasting with delay time longer than half of the energy peak period. The EMD method was used to identify delay time of millisecond blasting in Zijinshan open-pit mine. According to the identification results, the blasting parameters were optimized for controlling the blast-induced vibration and reducing the large block ratio. The field data showed that the velocity peak of ground vibration was reduced by more than 30%under almost the same maximum charge per delay by the optimization of delay time and detonating detonators. Combining with slag-remaining blasting and burden optimization of the first row, the large block ratio was reduced to less than 3%. The research results proved that the identification method based on HHT was feasible to optimize the blasting design. The identification method is also of certain reference value for design optimization of other similar blasting projects.展开更多
Reducing the blasting vibration is important for blasting excavation in subway tunnel construction.Taking the 3rd bid section of Line 3 of Qingdao subway project as an example,the distance between tunnel vault and gro...Reducing the blasting vibration is important for blasting excavation in subway tunnel construction.Taking the 3rd bid section of Line 3 of Qingdao subway project as an example,the distance between tunnel vault and ground is 5 ~ 8 m.In order to insure the safety of the upper buildings,technologies of parallel cut with large diameter empty hole,one-time initiation and delay by parts,and multiple shallow holes were adopted in the project.The results showed that the maximum value of vertical vibration was limited in the criterion allowance,and the upper buildings were not damaged.Besides,problems were solved that the number of nonel detonator was difficult to meet the requirements of excavating a large cross-section tunnel by blasting,multiple cross-section could’t be initiated simultaneously,and construction efficiency was low,which ensure the construction safety and schedule.展开更多
基金Project(2013BAB02B05)supported by the National 12th Five-Year Science and Technology Supporting Plan of ChinaProject(2015CX005)supported by the Innovation Driven Plan of Central South University of ChinaProject(2016zzts094)supported by the Fundamental Research Funds for the Central Universities of Central South University,China
文摘The accurate identification of delay time in millisecond blasting plays an important role in the optimization of blasting design and reduction of vibration effect. Through a case study of a surge shaft blasting project, the capability of the EMD （empirical mode decomposition） method in identifying the delay time of short millisecond blasting with precise initiation was compared with the instantaneous energy method based on Hilbert-Huang transform （HHT）. The recognition rate of the EMD method was more than 80%, while the instantaneous energy method was less than 25%. By analyzing the instantaneous energy of single-hole blasting signal, it was found that the instantaneous energy method was adaptable to millisecond blasting with delay time longer than half of the energy peak period. The EMD method was used to identify delay time of millisecond blasting in Zijinshan open-pit mine. According to the identification results, the blasting parameters were optimized for controlling the blast-induced vibration and reducing the large block ratio. The field data showed that the velocity peak of ground vibration was reduced by more than 30%under almost the same maximum charge per delay by the optimization of delay time and detonating detonators. Combining with slag-remaining blasting and burden optimization of the first row, the large block ratio was reduced to less than 3%. The research results proved that the identification method based on HHT was feasible to optimize the blasting design. The identification method is also of certain reference value for design optimization of other similar blasting projects.
文摘Reducing the blasting vibration is important for blasting excavation in subway tunnel construction.Taking the 3rd bid section of Line 3 of Qingdao subway project as an example,the distance between tunnel vault and ground is 5 ~ 8 m.In order to insure the safety of the upper buildings,technologies of parallel cut with large diameter empty hole,one-time initiation and delay by parts,and multiple shallow holes were adopted in the project.The results showed that the maximum value of vertical vibration was limited in the criterion allowance,and the upper buildings were not damaged.Besides,problems were solved that the number of nonel detonator was difficult to meet the requirements of excavating a large cross-section tunnel by blasting,multiple cross-section could’t be initiated simultaneously,and construction efficiency was low,which ensure the construction safety and schedule.
